Recent vehicles are equipped with various systems such as a navigation system, an audio system and a driving support system. This increases the opportunity to input text characters to these systems. It is demanded to develop a technology which enables a driver to input text characters as easily as possible.
Systems for inputting a text character can be roughly classified into the following two systems. A first system is that a single text character is selected and inputted from a list displaying all the text characters. A second system is that multiple text characters are assigned to an operation button (or a predetermined position on an operation panel) and a single text character is selected and inputted from the assigned text characters through multiple operations. For example, in the case of Japanese Hiragana which constitutes syllabic text characters, multiple text characters are assigned to an operation button on a group basis such as text characters in a “a” syllable group (a, i, u, e, o), text characters in a “ka” syllable group (ka, ki, ku, ke, ko) and the like.
Various technologies for these methods have been proposed to enable a simple input.
For example, a proposed technology (patent document 1) for the first input system (system for selecting and inputting from a list displaying text characters) is to display, responsive to input of the first text character, narrowed candidates of next inputs using a built-in dictionary, in order to simplify the text character input.
A proposed technology (patent document 2) for the second input system (system for selecting and inputting a text character through multiple operations of an operation button etc.) is to display, responsive to each operation of the operation button etc., the selected text characters on the operation button etc., so as to enable easy recognition of what text characters are presently selected.
According to studies by the inventor of the present application, the demand to easily input a text character cannot be fully satisfied by any of these proposed technologies. Specifically, the input system (the first input system) in which a desired text character is selected from a list displaying multiple text characters has a shortage of display screen size relative to the total number of displayed text characters, and thus, each individual text character cannot be displayed with a sufficient size. It becomes difficult to find a desired text character and select the found text character.
In the input system (the second input system) in which a text character is selected through multiple operations of the operation button (or the operation panel), the input of a desired text character requires multiple operations of the operation button (or the operation panel). It is impossible to input a text character promptly.
Therefore, the input of a text character cannot be easily performed in any of these input systems.